Premium
Ethanol‐evoked reduction in myocardial contractility and autonomic dysregulation in freely moving female rats
Author(s) -
Ibrahim Badr Mostafa,
Fan Ming,
AbdelRahman Abdel A
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.654.17
Subject(s) - contractility , medicine , blood pressure , heart rate , ethanol , cardiac function curve , endocrinology , cardiac output , cardiology , chemistry , anesthesia , heart failure , organic chemistry
Acute ethanol reduces blood pressure (BP) in proestrus female rats via reduction in cardiac output, which reflected reduced cardiac contractility based on indirectly measured d P /d t max (maximal rise of ventricular pressure over time). In this study we directly measured cardiac contractility indices [left ventricular developed pressure (LVDP), d P /d t max and the ventricular isovolumic relaxation time constant (Tau)] in conscious freely moving female rats via fluid filled catheter. We validated this technique using isoproterenol, which produced the expected dose‐related increases in d P /d t max . To test whether ethanol cardiac depressant effect precedes the hypotensive response in freely moving female rats, we directly measured cardiac function along with BP, HR, in two animal groups received either intragastric ethanol (1 g/kg) or water (control). Further, we conducted offline analysis of sympathovagal activity (spectral analysis) to elucidate ethanol effect on autonomic balance. Acute ethanol, compared to water, caused slowly developing reduction in BP that was significant at 40 min, reached its nadir at 70 min, and lasted till the experiment ended at 90 min. However, significant reductions in myocardial contractility indices (LVDP and d P /d t max ) started 10 min after ethanol, which preceded the hypotensive response. The high‐frequency (HFα) component of spectral analysis of RRI (cardiac vagal control) increased by intragastric ethanol starting at 20 min and continued throughout the experiment. However, the spectral measure of sympathetic activity, low‐frequency (LFα) component of RRI, was not affected by ethanol resulting in net decreases in the sympathovagal, LF RRI /HF RRI , ratio. Collectively, our findings directly implicate the reduction in cardiac contractility and enhancement of cardiac vagal control, at least partly, in acute ethanol‐evoked hypotensive effect in proestrus female rats. Supported by NIAAA Grant 2R01 AA14441–06